Recoverable tamping plug



y 1952 B. F. SANDERS 3,041,973

RECOVERABLE TAMPING PLUG 2 Sheets-Sheet 1 Filed March 27, 1959 BenjaminF Sanders IN VEN TOR. A. wax 2a". BY 5% B. F. SANDERS RECOVERABLETAMPING PLUG July 3, 1962 2 Sheets-Sheet 2 Filed March 27, 1959 Nb VbBen/0051b E Sanders ZNVENTOR. Mm BY and United States This inventioncomprises a novel and useful recoverable tamping plug and moreparticularly relates to an improved tamping plug adapted to tamp andretain blasting charges in a shot hole in an improved manner, and whichmay be recovered for re-use.

The primary purpose of this invention is to provide a tamping plug whichshall have an improved tamping action in a shot hole for retaining ablasting charge therein during the blasting operation; and which shallbe capable of repeated re-use.

Afurther object of the'invention is to provide a tamping plug whichshall include thereon means whereby the plug may be readily separatedfrom the material shot down by the blast and recovered for subsequentre-use.

A further and more specific object of'the invention is to provide atamping plug in accordance with the foregoing objects which shall beentirely constructed of a resiliently yieldable and deformable materialsuch as rubher or the like and which shall obtain an improved and moreeffective sealing engagement with the wall of the shot hole during theblasting operation.

Another specific object of the invention is to provide a tamping plug inaccordance with the foregoing objects which shall have mounted thereonone or more elements of a magnetic material whereby the tamping plug maybe recovered by electromagnetic means as the material shot down by theblast with the plugs therein are passed in close proximity to anelect-ro-magnet.

Still another and more specific object of the invention is to provide animprovedtamping plug consisting of an elongated rod-like body of rubberor other resiliently yieldable and deformable material having integralannular sealing rings along the'length thereof together with a pluralityof bands or rings of a magnetic material loosely encircling the bodywhereby the plug may be readily recovered from the material shot down bythe blast when the material and the plug are passed in close proximityto an'el'ectro-magnet.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed,'referencebeing had to the accom V panying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a view showing in vertical section a portion of a blast holein a formation together with a tamping plug in accordance with thisinvention applied in the blast hole for retaining a blasting chargetherein;

FIGURE 2 is a perspective view of the improved tamping plug inaccordance with the invention and as shown in FIGURE 1. 7

FIGURE 3 is a view in vertical central longitudinal section taken uponan enlarged scale substantially upon the plane indicated by the sectionline 33 of FIGURE 2 and with a portion thereof being broken away;

FIGURE 4 is a vertical transverse sectional view taken upon an enlargedscale substantially upon the plane indicated by the section line 44 ofFIGURE 2.

FIGURE 5 is an elevational view illustrating the manner in which amodified construction of tamping plug in accordance with this inventionis removed from the material shot down by the blast when the materialand plug are passed in proximity to an electro-magnet;

FIGURE 6 is an elevational view of the modified tamping plug employed inaccordance with the method indicated in FIGURE 5;

atent FIGURE 7 is a detail view in vertical central section takensubstantially upon the plane indicated by the section line 77 of FIGURE6; and

FIGURE 8 is a vertical transverse sectional view taken substantiallyupon the plane indicated by the section line 8,-8 of FIGURE 6.

Referring now to FIGURE 1 it will be observed that the numeral 10indicates a portion of a vein or other deposit of material which it isdesired to break up and recover as by blasting, while the numeral 12indicates a blast or shot hole therein. A blasting charge shown at 12 isshown tamped in this hole by the improved tamping plug of the presentinvention indicated generally by the numeral 14.

Referring now to FIGURES 2 and 3 in particular it will be observed thatthe tamping plug consists of a rodlike element 26 which is preferably ofuniform diameter throughout its end except for the provision of aplurality of longitudinally spaced annularly enlarged sealing rings asat 22. In addition, at its outer end the body 20 is provided with adiametrically enlarged flange or head portion as at 24 while the innerend of the body is diametrically enlarged as at 26 but of a diameterstill less than that of the rings 22 or the head 24, and thisdiametrically enlarged end portion is provided with a reversely' taperedconical surface as at 28 and 29. Upon its inner end,'the enlargement 26is provided with a recess or cavity 30 which is adapted to abut againstand tightly engage the charge 14 in the position shown inFIGURE l. Insome instances, the tamping of the plug against the charge will resultin causing the deformable yieldable material of the enlargement 26 toact as a suction cup and retain the plug against the charge.

The annular enlarged ribs or rings 22 of the plug are provided withdished surfaces as at 32 upon their sides which are adjacent to the head24 while the opposite sides of the plug are provided with doubled edgesas at 34. This construction causes the ribs to yield as the plug istamped or driven into the shot hole 12 and thus insuring theestablishing of a tight sealed engagement of the tamping plug with thewall of the hole. In a similar manner,-the inward surface of the head 24is likewise beveled as at 36 for the same purpose. The tapered end 28assists in guiding the tamping plug into the shot hole as previouslymentioned. 3

In this form of the invention the rubber plug when driven tightlyagainst the blasting charge 14 will by virtue of the flexing of itsfins, ribs or enlargements 22 against the wall of the shot hole effect atight seal engagement therewith. In addition, the suction cup eifect ofthe cavity 30 will assist in retaining the tamping plug tightly againstthe charge once the same is tamped into place.

After the blasting charge 14 is set off in the usual manner, the forceof the expanding gases being retained by the tamping plug will disruptor shoot down the formation 10 and thus break up the material of thesame. Thereafter, when this material is removed from the sight of theblasting operation, the rubber tamping plugs can be recovered therefromin any suitable manner and owing to their resilient nature will besuitable for re-use again and again.

However, shown in FIGURES 5-8 is a preferred embodiment of tamping plugin accordance with this invention which will facilitate the recovery ofthe plug by mechanical means. In this embodiment, it will be understoodthat the plug indicated generally by the numeral 50 likewise is anelongated rod-like body preferably of a resiliently yieldable deformablematerial such as rubber or the like. Intermediate its ends and inlongitudinally spaced relation therealong the body is provided with aplurality of annular laterally projecting ribs, fins or flanges as at 52which establish a resilient seal with the wall of the shot hole in whichthe plug is inserted. At its opposite ends the plug is provided withdiametrically enlarged end portions as at 54, one of which is adapted tobe positioned closely adjacent to or abutting against the blastingcharge while the other end comprising the outer end of the tamping plugis employed to tightly drive the plug into engagement with the charge.The body portion 56 of the plug has been illustrated as being of uniformdiameter. It will be understood, however, that this body may be of anydesired 'cross sectional shape or area and may be of a variablethickness or diameter depending upon the circumstances in which the plugis to be employed.

Although the annular sealing flanges or ribs 52 and the ends 54 areshown as being rectangular in cross-section as seen in FIGURE 7 and itwill be understood that they may be of the same construction shown inFIGURE 3, so that the dished surfaces 32, the bevel surfaces 34, 36, thetapered surfaces 28 and 29 and the recess 30 may all likewise beemployed.

At longitudinally spaced positions along a rod-like body 56 there aresecured magnetic elements 60. Preferably these elements 60' are in theform of loosely encircling bands or rings which are received upon thebody between adjacent rings of flanges 52 or between the latter and oneof the ends 54. In some instances, however, the rings 60 may be tightlysecured to the rod-like member as by being embedded in annular groovestherein or the like. In other instances, the magnetic elements may be inthe form of separate bodies of magnetic material embedded in or securedin any desired manner to the body portion of the tamping plug.

The purpose of the application of the magnetic elements to the body willbe readily apparent from FIGURE 5. After the blasting charge has beenset off and the material 10 has been shot down from the face of theblasting operation, the thus broken up material as at 70 in FIGURE 5,with one or more of the plugs 50 disposed therein is caused to pass withthe material into close proximity to an electro-magnet as at 72. Thismagnet will attract the magnetic material of the plugs passing in closeproximity thereto and thus draw or remove the plug from the materialwhereby the plugs may be reclaimed for further use. It will beunderstood that the electro-magnetic recovery device may be disposed inany suitable position as in a colliery if the plugs are employed in theblasting of coal, or anywhere along the passage of the shot material.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. A recoverable and reusable tamping plug for blasting comprising aunitary elongated rod-like and solid body of a non-magnetic resilientlyyieldable and deformable material for insertion in shot holes, integralannularly enlarged sealing rings on said body in longitudinally spacedrelation thereon and of a diameter and resiliency suflicient to enter ashot hole and thereafter establish a sealing engagement with a shot holeWall in which the tamping plug is inserted, a magnetic elementsurrounding said body between a pair of adjacent rings whereby tofacilitate recovery of the plug from the material shot down by the blastwith a magnetic plug recovery device, a tapered inwardly recessed innerend on said plug to facilitate its insertion into a shot hole and itsposition against a blasting charge therein.

2. The combination of claim 1 including a pair of longitudinally spacedmagnetic elements mounted upon said plug each at one end thereof wherebyto effect recovery of said plug from the material shot down by the blastwith a magnetic plug recovery device.

3. The combination of claim 1 including a plurality of longitudinallyspaced magnetic elements mounted upon said plug whereby toeffectrecovery of said plug from the material shot down by the blastwith a magnetic plug recovery device, said elements comprising bandsdisposed each between a pair of adjacent rings and of less diameter thanthat of said rings and loosely encircling said plug.

References Cited in the file of this patent UNITED STATES PATENTS I52,836 Felt Feb. 27, 1866 ,2,129,439 Noble Sept. 6, 1938 2,428,884Lefren Oct. 14, 1947 2,449,645 DuPont Sept. 21, 1948 2,818,809 Roy Jan.7, 1958 2,916,995 Douglass et a1 Dec. 15, 1959 FOREIGN PATENTS 1,039,136France May 13, 1953 1,039,203 7 France May 13, 1953 949,633 GermanySept. 20, 1956

